1. Field of the Invention
The present invention relates to electronic components, and more particularly to an electronic component including a directional coupler.
2. Description of the Related Art
As one example of electronic components in the related art, a bandpass filter described in Japanese Patent No. 4432059 is known. This bandpass filter includes a three-stage LC parallel resonator and a sub line. In the three-stage LC parallel resonator, three stages of LC parallel resonators are arranged in one line, and each LC parallel resonator is electromagnetically coupled to an adjacent LC parallel resonator. The sub line is electromagnetically coupled to inductors of the respective LC parallel resonators. In such a bandpass filter described above, a signal having the power proportional to the power of a signal passing through the three-stage LC parallel resonator is outputted from a port connected to the sub line.
In the bandpass filter described in Japanese Patent No. 4432059 uses the three-stage LC parallel resonator. Having different resonance frequencies in the three-stage LC parallel resonator allows the bandpass filter to form a desired pass band. However, to obtain a broader pass band, a larger number of LC parallel resonators are needed. This raises an issue of size increase in the bandpass filter.